1. Field of the Invention
The invention relates to an apparatus for filling beverage containers (1) under an inert gas atmosphere, the apparatus having a stationary filling tool (20) to which are led the containers and implements to fill the containers with inert gas prior to the filling procedure.
2. Description of Related Art
Beverages such as beer, lemonades, cocoa etc. are filled into rigid containers such as glass bottles and furthermore into pliant containers such as thin-walled plastic bottles and, before closing, highly pliant metal cans or plastic pouches.
Many beverages are susceptible to oxygen and therefore must be filled into containers in an atmosphere of inert gas, typically CO2, in order to prevent taste alterations and other degradations in quality caused by oxygen entering the container during filling.
As regards highly dimensionally stable containers such as glass bottles or thick-walled plastic bottles, it is known to seal the containers at the site of the filling tool and to fill the containers with inert gas before filling same with the beverage. This procedure entails a complex sealing system and, furthermore, a device implementing the sealing action. Such sealing is very expensive as regards special containers and, in particular, pliant containers. Operational problems may arise. Pliant containers may be over-stretched when being filled with inert gas. In every case they are warped by such procedures and substantial operational difficulties may ensue.
An objective of the present invention is to create a beverage filling apparatus of the above kind which is of simple design and offers high operational reliability while allowing filling in the presence of only very low oxygen levels.
In the apparatus of the invention, the containers move through the entry sluice or buffer space into the processing chamber loaded with inert gas where they will be filled with inert gas. By pre-conditioning the containers at the sluice or buffer space, the contamination of the inert gas with air, that is the air exchange with the processing chamber, can be minimized. Illustratively the entry sluice space may be flushed with inert gas in order to lower the air contents in the containers before they are moved into the processing chamber. Because the containers within the processing chamber are in an inert-gas atmosphere, the filling tool need not be sealed. Accordingly, the filling tool""s design can be substantially simplified. Therefore filling can take place in and xe2x80x9copenxe2x80x9d state in the processing chamber. Accordingly special bottles and, in particular, pliant containers can be filled in problem-free manner.
Advantages are secured especially with respect to highly pliant containers because these containers are subjected to the same pressure outside and inside within the processing chamber and, therefore, will not be stressed at their walls. The apparatus of the invention need only provide a slight excess pressure in the processing chamber to preclude air entering trough sealing leaks. Non-carbonated beverages may be filled while open within the processing chamber, the chamber also allowing filling beverages with CO2 at higher pressures, in which case a container at the filling tool would have to be sealed during filling. However, the full CO2 pressure may also be set in the processing chamber to fill carbonated beverages. In this case as well the seal between container and filling tool may be eliminated.
In further accordance with the present invention, it is possible in an especially efficacious manner to drag air into the inert gas atmosphere of the processing chamber. Moreover, the container, or at least its cover with fasteners to the container, is sealed inside the processing chamber under inert gas, and the air is prevented from penetrating the top container space after this container has been filled.
The container can be removed from the controlled atmosphere of the processing chamber in a manner which is the reverse of its introduction into the processing chamber. Advantageously, however, the containers are moved in a sluice-conditioned manner into and out of the processing chamber at increased processing speed. The exit buffer or sluice space prevents air-contamination of the processing chamber and pumping back inert gas saves material. Advantageously, moreover, inert gas also may be pumped back from the first sluice space into the processing chamber so that this processing chamber then be externally opened to receive the new container.
In further accordance with the present invention, container sterilization required for micro-organism sensitive beverages such as cocoa, iced tea and the like is integrated in simple manner into the beverage filling apparatus. The first sluice space is especially appropriate for this procedure because it is kept very clean by constantly being evacuated.
In accordance with another feature of the invention, the sterilizing system uses low-pressure plasma sterilization, which is advantageous, and the evacuation system used anyway may be used for attaining the low pressure.
In further accordance with the present invention, an evacuation-generated partial vacuum exists in the first sluice space, before its door to the processing chamber is opened, while for good sealing the inert gas is at slightly reduced pressure in the processing chamber. If the entry sluice-space door is opened abruptly, inert gas enters the entry sluice space as a pulse and might press inward a highly pliant container wall or it also might tip the container. If a vent of small cross-section is opened before the sluice-space door is, then the flooding of the first sluice space takes place gradually without affecting the container.
In further accordance with the present invention, the filling tool need enter the processing chamber only by its portion which engages the container, that is its lower end with the discharge element. The remaining elements remaining elements of the filling tool are advantageously configured outside the processing chamber and, for instance, are accessible for maintenance. As a result the processing chamber can be kept very compact and those elements of the filling tool requiring maintenance are externally accessible. In the same manner other components also present inside the processing chamber, in particular sealing components, may be configured so that their parts not touching the container shall be outside the processing chamber.
In further accordance with the present invention, a series beverage-filling apparatus are provided to fill containers in timed manner in parallel lines. In this manner the filling output is substantially increased.